An optical navigation device, such as an optical mouse, typically includes an optical navigation sensor integrated circuit (IC) that functions as a miniature digital camera to continually collect images of a surface that the device is disposed on, and to determine the speed and direction at which the device is being moved across the surface by comparing sequentially recorded frames of image information. Image frames are collected at a very high rate, such as one image frame per fraction of a millisecond, and the resolution of the optical navigation sensor is generally high enough to detect very small movements of the device relative to the surface.
Conventional optical navigation devices have typically operated at a single, fixed dot per inch (dpi) resolution, for example, at either 400 dpi or 800 dpi. Some gaming mouse devices allow a user to change the dpi resolution, e.g., via a device-specific software driver, such that the device can be operated at one of a few pre-set resolution levels, for example, at 400, 800, 1600, or 2000 dpi.
A disadvantage of the prior art is that the pointing device can only be operated at one of a few pre-set resolution levels. A further disadvantage of the prior art is that the pre-set resolution levels typically differ by large dpi increments, e.g., several hundreds of dpi. These disadvantages are compounded by the problem known as cursor jitter. In general, the higher the resolution, the greater the jitter. Cursor jitter can severely limit a user's ability to navigate using an optical pointing device at relatively high resolution levels. Because 1) the amount of jitter that occurs can vary widely, e.g., depending on the tracking surface, and 2) the amount of jitter that can be tolerated will depend on the particular user and the circumstances, e.g., the type of work or game for which the mouse is being used, conventional mice, which have only a few pre-programmed dpi values that differ by relatively large dpi increments, are often not useful in addressing jitter problems. Cursor jitter has been a primary constraint to increasing dpi resolution of optical pointing devices above about 2,000 dpi, even when the pointing device is used on a suitable tracking surface such as a mouse pad.
Thus, there is a need for a pointing device operable over a wide range of variable, smaller increment resolution values, wherein the resolution is controlled or adjusted by the user, and the pointing device is adaptable to a broad spectrum of navigation situations, individual users, and different surfaces.